Energy saving papermaking forming apparatus, system, and method for lowering consistency of fiber suspension

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent Application Ser. No. 61/510,378 filed Jul. 21, 2011, which is incorporated by reference herein.

The present application is related to U.S. patent application Ser. No. 13/020,462 filed Feb. 3, 2011, now U.S. Pat. No. 8,163,136 granted Apr. 24, 2012, which claims priority to U.S. Provisional Patent Application Ser. No. 61/423,977 filed Dec. 16, 2010, the entirety of each of which is incorporated by reference herein.

FIELD OF THE INVENTION

The present invention is directed to an apparatus used in the formation of paper. More specifically the present invention is directed to an apparatus, system, and method for lowering the consistency or degree of density of fiber suspension on the forming table, and improving the quality and physical properties of the paper formed thereon.

BACKGROUND OF THE INVENTION

In general, it is well known in the papermaking industry that proper drainage of liquid from the paper stock on a forming fabric is an important step to ensure a quality product. This is done through the use of drainage blades or foils usually located at the wet end of the machine, e.g. a Fourdrinier paper machine. (Note the term drainage blade, as used herein, is meant to include blades or foils that cause drainage or stock activity or both.) A wide variety of different designs for these blades are available today. Typically, these blades provide for a bearing or support surface for the wire or forming fabric with a trailing portion for dewatering, which angles away from the wire. This creates a gap between the blade surface and the fabric, which causes a vacuum between the blade and the fabric. This not only drains water out of the fabric, but also can result in pulling the fabric down due to suction. However, when the vacuum collapses, the fabric returns to its original position, which can result in a pulse across the stock, which may be desirable for stock distribution. The activity (caused by the wire deflection) and the amount of water drained from the sheet are directly related to vacuum generated by the blade. Drainage and activity by such blades can be augmented by placing the blade or blades on a vacuum chamber. The direct relationship between drainage and activity is not desirable because while activity is always desirable, too much drainage early in the sheet formation process may have adverse effects on retention of fibers and filler. Rapid drainage may also cause sheet sealing, making subsequent water removal more difficult. Existing technology forces the paper maker to compromise desired activity in order to slow early drainage.

Drainage can be accomplished by way of a liquid to liquid transfer such as that taught in U.S. Pat. No. 3,823,062 to Ward, which is incorporated herein by reference. This reference teaches the removal of liquid through sudden pressure shocks to the stock. The reference states that controlled liquid to liquid drainage of water from the suspension is less violent than conventional drainage.

A similar type of drainage is taught in U.S. Pat. No. 5,242,547 to Corbellini. This patent teaches preventing the formation of a meniscus (air/water interface) on the surface of the forming fabric opposite the sheet to be drained. This reference achieves this by flooding the vacuum box structure containing the blade(s) and adjusting the draw off of the liquid by a control mechanism. This is referred to as “Submerged Drainage.” Improved dewatering is said to occur through the use of sub-atmospheric pressure in the suction box.

In addition to drainage, blades are constructed to purposely create activity in the suspension in order to provide for desirable distribution of the stock. Such a blade is taught, for example, in U.S. Pat. No. 4,789,433 to Fuchs. This reference teaches the use of a wave shaped blade (preferably having a rough dewatering surface) to create micro-turbulence in the fiber suspension.

Other types of blades wish to avoid turbulence, but yet affect drainage, such as that described, for example, in U.S. Pat. No. 4,687,549 to Kallmes. This reference teaches filling the gap between the blade and the web, and states that the absence of air prevents expansion and ‘cavitation’ of the water in the gap and substantially eliminates any pressure pulses. A number of such blades and other arrangements can be found in the following prior art: U.S. Pat. Nos. 5,951,823; 5,393,382; 5,089,090; 4,838,996; 5,011,577; 4,123,322; 3,874,998; 4,909,906; 3,598,694; 4,459,176; 4,544,449; 4,425,189; 5,437,769; 3,922,190; 5,389,207; 3,870,597; 5,387,320; 3,738,911; 5,169,500 and 5,830,322, which are incorporated herein by reference.

Traditionally, high and low speed paper machines produce different grades of paper with a wide range of basis weights. Sheet forming is a hydromechanical process and the motion of the fibers follow the motion of the fluid because the inertial force of an individual fiber is small compared to the viscous drag in the liquid. Formation and drainage elements affect three principle hydrodynamic processes, which are drainage, stock activity and oriented shear. Liquid is a substance that responds according to shear forces acting in or on it. Drainage is the flow through the wire or fabric, and it is characterized by a flow velocity that is usually time dependant. Stock activity, in an idealized sense, is the random fluctuation in flow velocity in the undrained fiber suspension, and generally appears due to a change in momentum in the flow due to deflection of the forming fabric in response to drainage forces or as being caused by blade configuration. The predominant effect of stock activity is to break down networks and to mobilize fibers in suspension. Oriented shear and stock activity are both shear-producing processes that differ only in their degree of orientation on a fairly large scale, i.e. a scale that is large compared to the size of individual fibers.

Oriented shear is shear flow having a distinct and recognizable pattern in the undrained fiber suspension. Cross Direction (“CD”) oriented shear improves both sheet formation and test. The primary mechanism for CD shear (on paper machines that do not shake) is the creation, collapse and subsequent recreation of well defined Machine Direction (“MD”) ridges in the stock of the fabric. The source of these ridges may be the headbox rectifier roll, the head box slice lip (see e.g., International Application PCT WO95/30048 published Nov. 9, 1995) or a formation shower. The ridges collapse and reform at constant intervals, depending upon machine speed and the mass above the forming fabric. This is referred to as CD shear inversion. The number of inversions and therefore the effect of CD shear is maximized if the fiber/water slurry maintains the maximum of its original kinetic energy and is subjected to drainage pulses located (in the MD) directly below the natural inversion points.

In any forming system, all these hydrodynamic processes may occur simultaneously. They are generally not uniformly distributed in either time or space, and they are not wholly independent of one another; they interact. In fact, each of these processes contributes in more than one way to the overall system. Thus, while the above-mentioned prior art may contribute to some aspect of the hydrodynamic processes aforesaid, they do not coordinate all processes in a relatively simple and effective way.

Stock activity in the early part of a Fourdrinier table as mentioned earlier is critical to the production of a good sheet of paper. Generally, stock activity can be defined as turbulence in the fiber-water slurry on the forming fabric. This turbulence takes place in all three dimensions. Stock activity plays a major part in developing good formation by impeding stratification of the sheet as it is formed, by breaking up fiber flocks, and by causing fiber orientation to be random.

Typically, stock activity quality is inversely proportional to water removal from the sheet; that is, activity is typically enhanced if the rate of dewatering is retarded or controlled. As water is removed, activity becomes more difficult because the sheet becomes set, the lack of water, which is the primary media in which the activity takes place, becomes scarcer. Good paper machine operation is thus a balance between activity, drainage and shear effect.

The capacity of each forming machine is determined by the forming elements that compose the table. After a forming board, the elements which follow have to drain the remaining water without destroying the mat already formed. The purpose of these elements is to enhance the work done by the previous forming elements.

As the basis weight is increased, the thickness of the mat is increased. With the actual forming/drainage elements it is not possible to maintain a controlled hydraulic pulse strong enough to produce the hydrodynamic processes necessary to make a well-formed sheet of paper.

An example of conventional means for reintroducing drainage water into the fiber stock in order to promote activity and drainage can be seen in <figref idrefs="DRAWINGS">FIGS. 1-4</figref>.

A table roll <b>100</b> in <figref idrefs="DRAWINGS">FIG. 1</figref> causes a large positive pressure pulse to be applied to the sheet or fiber stock <b>96</b>, which results from water <b>94</b> under the forming fabric <b>98</b> being forced into the incoming nip formed by the lead in roll <b>92</b> and forming fabric <b>98</b>. The amount of water reintroduced is limited to the water adhered to the surface of the roll <b>92</b>. The positive pulse has a good effect on stock activity; it causes flow perpendicular to the sheet surface. Likewise, on the exiting side of the roll <b>90</b>, large negative pressures are generated, which greatly motivate drainage and the removal of fines. But reduction of consistency in the mat is not noticeable, so there is little improvement through increase in activity. Table rolls are generally limited to relatively slower machines because the desirable positive pulse transmitted to the heavy basis weight sheets at specific speeds becomes an undesirable positive pulse that disrupts the lighter basis weight sheets at faster speeds.

<figref idrefs="DRAWINGS">FIGS. 2 to 4</figref> show low vacuum boxes <b>84</b> with different blade arrangements. A gravity foil is also used in low vacuum boxes. These low vacuum augmented units <b>84</b> provide the papermaker a tool that significantly affects the process by controlling the applied vacuum and the pulse characteristics. Examples of blade box configurations include:

Step blades <b>82</b> as show in <figref idrefs="DRAWINGS">FIGS. 2-3</figref>; and

Positive pulse step blade <b>78</b>, as shown in <figref idrefs="DRAWINGS">FIG. 4</figref>, for example. Traditionally, the foil blade box, the offset plane blade box and the step blade box are mostly used in the forming process.

In use, a vacuum augmented foil blade box will generate vacuum as the gravity foil does, the water is removed continuously without control, and the predominant drainage process is filtration. Typically, there is no refluidization of the mat that is already formed.

In a vacuum augmented flat blade box, a slight positive pulse is generated over the blade/wire contact surface and the pressure exerted on the fiber mat is due only to the vacuum level maintained in the box.

In a vacuum augmented step blade box, as shown in <figref idrefs="DRAWINGS">FIG. 2</figref> for example, a variety of pressure profiles are generated depending upon factors such as, step length, span between blades, machine speed, step depth, and vacuum applied. The step blade generates a peak vacuum relative to the square of the machine speed in the early part of the blade, this peak negative pressure causes the water to drain and at the same time the wire is deflected toward the step direction, part of the already drained water is forced to move back into the mat refluidizing the fibers and breaking up the flocks due to the resulting shear forces. If the applied vacuum is higher than necessary, the wire is forced to contact the step of the blade, as shown in <figref idrefs="DRAWINGS">FIG. 2</figref>. After some time of operation in such a condition, the foil accumulates dirt <b>76</b> in the step, losing the hydraulic pulse which is reduced to the minimum, as shown in <figref idrefs="DRAWINGS">FIG. 3</figref>, and prevents the reintroduction of water into the mat.

The vacuum augmented positive pulse step blade low vacuum box, as shown in <figref idrefs="DRAWINGS">FIG. 4</figref>, fluidizes the sheet by having each blade reintroduce part of the water removed by the preceding blade back into the mat. There is, however, no control on the amount of water reintroduced into the sheet.

Positive pulse blade, as water drains through the fabric, a converging nip produced by the lead angle of the blade and the fabric forces the water back into the sheet. This produces a shear force capable of breaking the fiber mat and penetrating through the stock slurry, re-fluidizing of the slurry is minimum, as it is shown in <figref idrefs="DRAWINGS">FIG. 5</figref>, for example.

A special type of double posi-blade incorporates a positive incoming nip to generate a positive and negative pressure pulse. This blade reintroduces water to the fiber mat with the lead in edge, the water reintroduced is limited to the amount adhere to the bottom of the forming fabric. This type of blade creates pressure pulses rather than consistency reduction. This type of blade simulates a table roll, as it is shown in <figref idrefs="DRAWINGS">FIG. 6</figref>, for example.

U.S. Pat. No. 5,830,322 to Cabrera et al., filed February 1996, titled “Velocity induced drainage method and unit” describes an alternate means of creating activity and drainage. The apparatus described therein decouples activity and drainage and thus presents a means of controlling and optimizing them. It uses a long blade with a controlled, probably non-flat or partially non-flat surface to induce initial activity in the sheet, and limits the flow after the blade through placement of a trail blade to control drainage. The '322 patent discloses that drainage is enhanced if the area between the long blade and forming fabric is flooded and surface tension is maintained between the water above and below the fabric. The invention disclosed therein is shown schematically in <figref idrefs="DRAWINGS">FIG. 7</figref>, for example.

However, with the '322 patent there is only one way to reintroduce a minimum amount of water to the fiber suspension. It occurs in the “counterflow zone,” and exists because the incompressible fluid follows the non-flat top of the long blade and is thus pumped through the forming fabric. The consistency that reaches the lead in edge of the Velocity Induce Unit does not change along the same blade. The stock consistency will be increased when the stock reaches the trial blade, because of drained water in the slot, if the Velocity Induce Unit is designed with multiple long blades and the consistency is constantly increased along the Velocity Induce Unit.

While some of the foregoing references have certain attendant advantages, further improvements and/or alternative forms, are always desirable.

SUMMARY OF THE INVENTION

Stock dilution on the forming section of the paper machine is critical to the production of a good sheet of paper. Generally, stock dilution is achieved at the short loop system of the forming section of the machine by increasing the recirculation of the white water.

Stock dilution on the forming table plays a major part in developing good formation, facilitates the realization of the three hydrodynamic processes necessary to make a well-formed sheet of paper; allowing the fiber orientation to be random.

Most of the paper machines have been sped up in order to increase production and have lower consistencies for better paper quality and still have the same machine screen, same piping and same headbox to supply water and stock to the forming table. The forming tables have been reworked in order to take care of the excessive flow.

Let us suppose as an example a paper machine originally designed with a headbox 200 inches wide, at a speed of 800 feet per min with a headbox consistency of 0.65%, making paper of 54 grams per square meter and a retention of 70%; the calculated flow out of the headbox will be about 3927 Gallons per minute. However, over the years the machine has increased the speed 1.75 times and the headbox consistency has been lowered for better quality to 0.38%, the retention has dropped to 65%; the flow out of the headbox is now about 12660 Gallons per minute. The flow has increased 3.22 times and as a result all internal velocities in the entire system have more than tripled, which may have harmful results.

Therefore, when working at low consistencies or when the paper machine is sped up, it is necessary to increase the number of drainage elements, because of the increased flow out of headbox. In some instances it is also necessary to increase the longitude of the table in order to make space for the installation of additional drainage equipment or to install new vacuum assisted drainage equipment.

However, due to the present invention, it is not necessary to increase the longitude of the table or to install new vacuum assisted drainage equipment. Additionally, there is a considerable reduction of energy consumption on the forming table.

Accordingly, an object of the present invention is to provide a machine for maintaining the hydrodynamic processes on the forming table irrespective of what the machine speed.

It is a further object of the present invention to provide a machine usable with a forming board and or a velocity induced drainage machine.

It is a further object of the present invention that the efficiency of the machine not be affected by the velocity of the machine, the basis weight of the paper sheet and or the thickness of the mat.

The present invention describes a machine that recycles the water by itself in order to dilute the fiber suspension on the table to the desired levels after the head box; the dilution rate of the present invention may be anything between 0% to 100%; the work done by the machine in the present invention is not affected by the degree of refining, velocity of the machine, the basis weight of the paper sheet or the thickness of the mat. After the sheet has been formed by the present invention, the drainage and the consolidation of the sheet is done by the equipment in continuation.

Paper making chemicals as known to those of ordinary skill in the art can be added to fiber suspension in order to enhance paper strength and machine productivity. All paper chemicals are added before or after the forming table.

One exemplary embodiment of the present invention is an apparatus for lowering consistency or degree of density of fiber contained in a liquid suspension on a forming table of a papermaking machine, the apparatus comprising at least one conduit for adding paper making chemicals into a flow of liquid to form a mixed flow, a forming fabric on which a fiber slurry is conveyed, the forming fabric having an outer surface and an inner surface, and a primary blade having a leading edge support surface that is in sliding contact with the inner surface of the forming fabric, a central plate that comprises at least a portion of self dilution, shear, microactivity or drainage section of the forming table, wherein the central plate is separated from a bottom plate by a predetermined distance to form a channel for recirculation of at least a portion of the liquid. The papermaking machine is configured such that mixed flow including a drained liquid to be re-used in at least a part of the forming process.

Another exemplary embodiment of the present invention is a system for lowering consistency or degree of density of fiber contained in a liquid suspension on a forming table of a papermaking machine, the system comprising an apparatus comprising at least one conduit for adding paper making chemicals into a flow of liquid to form a mixed flow, a forming fabric on which a fiber slurry is conveyed, the forming fabric having an outer surface and an inner surface, a primary blade having a leading edge support surface that is in sliding contact with the inner surface of the forming fabric, a central plate that comprises at least a portion of self dilution, shear, microactivity or drainage section of the forming table, wherein the central plate is separated from a bottom plate by a predetermined distance to form a channel for recirculation of at least a portion of the liquid. The papermaking machine such that mixed flow including a adrained liquid can be re-used in at least a part of the forming process.

Another exemplary embodiment of the present invention is a method for lowering consistency or degree of density of fiber suspension on a forming table of a papermaking machine, the method comprising the steps of providing a forming fabric on which a fiber slurry is conveyed, the forming fabric having an outer surface and an inner surface, providing a primary blade having a leading edge support surface that is in sliding contact with the inner surface of the forming fabric, and providing a central plate that comprises at least a portion of self dilution, shear, microactivity or drainage section of the forming table, wherein the central plate is separated from a bottom plate of the forming table by a predetermined distance to form a channel for recirculation of at least a portion of the liquid.

The various features of novelty which characterize the invention are pointed out in particularity in the following description of preferred embodiments. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which preferred embodiments of the invention are illustrated.

BRIEF DESCRIPTION OF THE DRAWINGS

The following detailed description, given by way of example and not intended to limit the present invention solely thereto, will best be appreciated in conjunction with the accompanying drawings, wherein like reference numerals denote like elements and parts, in which:

<figref idrefs="DRAWINGS">FIG. 1</figref> Depicts a known table roll;

<figref idrefs="DRAWINGS">FIG. 2</figref> Depicts a known low-vacuum box with step blade;

<figref idrefs="DRAWINGS">FIG. 3</figref> Depicts a known low-vacuum box, step blade with dirt accumulation;

<figref idrefs="DRAWINGS">FIG. 4</figref> Depicts a known positive pulse blade low vacuum box;

<figref idrefs="DRAWINGS">FIG. 5</figref> Depicts a known positive pulse blade;

<figref idrefs="DRAWINGS">FIG. 6</figref> Depicts a known double positive pulse blade;

<figref idrefs="DRAWINGS">FIG. 7</figref> Depicts a known velocity induced drainage unit;

<figref idrefs="DRAWINGS">FIG. 8</figref> Depicts a water recirculation system in a paper machine;

<figref idrefs="DRAWINGS">FIG. 9</figref> Depicts headbox flow discharged on top of a forming wire;

<figref idrefs="DRAWINGS">FIG. 10</figref> Depicts mass balance at 0.8% consistency out of headbox;

<figref idrefs="DRAWINGS">FIG. 11</figref> Depicts mass balance at 0.5% consistency out of headbox;

<figref idrefs="DRAWINGS">FIG. 12</figref> Depicts the mass balance according to one embodiment of the present invention;

<figref idrefs="DRAWINGS">FIG. 13</figref> Depicts the new forming invention;

<figref idrefs="DRAWINGS">FIG. 13A</figref> Depicts the new forming invention showing the chemical injection;

<figref idrefs="DRAWINGS">FIG. 13B</figref> Depicts the new forming invention, details the chemical injection.

<figref idrefs="DRAWINGS">FIG. 14</figref> Depicts another aspect of the new forming invention with different lead in blade <b>42</b>;

<figref idrefs="DRAWINGS">FIG. 15</figref> Depicts another aspect of the new forming invention with different lead in blade <b>44</b>;

<figref idrefs="DRAWINGS">FIG. 16</figref> Depicts another aspect of the new forming invention without support blade;

<figref idrefs="DRAWINGS">FIG. 17</figref> Depicts another aspect of the new forming invention, the self dilution, shear, microactivity and drainage section with pivot point;

<figref idrefs="DRAWINGS">FIG. 18</figref> Depicts another aspect of the new forming invention, the self dilution, shear, microactivity and drainage section with pivot point, changing the angle of the drainage section;

<figref idrefs="DRAWINGS">FIG. 19</figref> Depicts another aspect of the new forming invention, details the hydraulic performance at the self dilution, shear, microactivity and drainage section with multiple converging and diverging sections;

<figref idrefs="DRAWINGS">FIG. 20</figref> Depicts another aspect of the new forming invention, which details the geometry of a long self dilution, shear, microactivity and drainage section with multiple converging and diverging sections;

<figref idrefs="DRAWINGS">FIG. 21</figref> Flow sheet that depicts the location of the new invention <b>75</b> at the wet end of a paper machine with the new invention as it is described in <figref idrefs="DRAWINGS">FIG. 13</figref>;

<figref idrefs="DRAWINGS">FIG. 22</figref> Flow sheet that depicts the location in detail of the new invention <b>75</b> at the wet end of a paper machine as it is described in <figref idrefs="DRAWINGS">FIG. 13</figref>;

<figref idrefs="DRAWINGS">FIG. 23</figref> Flow sheet that depicts the location of the new invention <b>76</b> at the wet end of a paper machine with the new invention as it is described in <figref idrefs="DRAWINGS">FIG. 20</figref>;

<figref idrefs="DRAWINGS">FIG. 24</figref> Flow sheet that depicts the location in detail of the new invention <b>76</b> at the wet end of a paper machine, as it is described in <figref idrefs="DRAWINGS">FIG. 20</figref>;

<figref idrefs="DRAWINGS">FIG. 25</figref> Depicts another aspect of the new forming invention, details the blade geometry of the long self dilution, shear, microactivity and drainage sections with same distance between the forming fabric and the surface of the central plate <b>48</b> with multiple forming fabric supports;

<figref idrefs="DRAWINGS">FIG. 26</figref> Depicts another aspect of the new forming invention, details the central plate geometry with multiples self dilution, shear, microactivity and drainage sections increasing the distance between the forming fabric and the surface of the central plate <b>49</b> with multiple forming fabric supports;

<figref idrefs="DRAWINGS">FIG. 27</figref> Depicts another aspect of the new forming invention, details the central plate with multiples self dilution, shear, microactivity and drainage sections with offset plane surfaces between the forming fabric and the surface of the central plate with multiple forming fabric supports;

<figref idrefs="DRAWINGS">FIG. 28</figref> Depicts another aspect of the new forming invention, which details the geometry of the offset plane section on the self dilution, shear, microactivity and drainage sections;

<figref idrefs="DRAWINGS">FIG. 29</figref> Depicts another aspect of the new forming invention, with details view geometry of the long self dilution, shear, microactivity and drainage section with pivot point at the drainage section;

<figref idrefs="DRAWINGS">FIG. 30</figref> Depicts another aspect of the new forming invention, with detail explanation of the hydraulics at the self dilution, shear, microactivity and drainage section including explanation of stream lines;

<figref idrefs="DRAWINGS">FIG. 31</figref> Depicts another aspect of the new forming invention, with detail explanation of the hydraulics at the self dilution, shear, microactivity and drainage section including explanation of stream lines with two blade supports in order to reduce wire deflection;

<figref idrefs="DRAWINGS">FIG. 32</figref> Depicts another aspect of the new forming invention, with detail explanation of the hydraulics at the self dilution and shear section;

<figref idrefs="DRAWINGS">FIG. 33</figref> Depicts another aspect of the new forming invention, shows detailed geometry of one system for holding the central plate;

<figref idrefs="DRAWINGS">FIG. 34</figref> Depicts another aspect of the new forming invention, shows details geometry of another system for holding the central plate;

<figref idrefs="DRAWINGS">FIG. 35</figref> Depicts details geometry of the T bar used to hold the central plate <b>35</b> and or any blade;

<figref idrefs="DRAWINGS">FIG. 36</figref> Depicts the hydraulic performance at self dilution and shear zone <b>54</b> of the new invention;

<figref idrefs="DRAWINGS">FIG. 37</figref> Depicts the hydraulic performance at low consistency microactivity zone <b>55</b> of the new invention;

<figref idrefs="DRAWINGS">FIG. 38</figref> Depicts the hydraulic performance at drainage zone <b>56</b> of the new invention;

<figref idrefs="DRAWINGS">FIG. 39</figref> Depicts another design of the hydraulic performance at drainage zone <b>56</b> of the new invention.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

All devices already described as a part of the previous art are part of or form the gravity and dynamic drainage zone or sheet formation zone <b>4</b> shown in <figref idrefs="DRAWINGS">FIG. 8</figref>.

Shown in <figref idrefs="DRAWINGS">FIG. 8</figref> is a system that is capable of reducing consistency at any level on the forming table. Thick stock <b>20</b>, often having a consistency of about 1 to 5% is diluted with white water <b>17</b> at the inlet <b>33</b> of the fan pump <b>24</b>; the necessary amount of thick stock is controlled by valve <b>21</b>. The fan pump <b>24</b> propels the dilute slurry of papermaking furnish towards the cleaning system <b>27</b> which removes all debris and non desirable objects <b>28</b>, and the clean stock is sent to headbox <b>1</b> of the paper machine. The consistency of thin-stock furnish coming out of the cleaning system <b>27</b> and <b>32</b> is typically between 0.1% and 1% solids.

Fan pump <b>24</b> and cleaning system <b>27</b> and <b>32</b> are typically located in the basement underneath the forming section of the paper machine. The stock is delivered from the headbox <b>1</b> onto the Fourdrinier wire <b>11</b> through a slice <b>2</b>. The total flow discharged over the forming wire <b>11</b> by the slice lip <b>2</b> of the head box <b>1</b>, is controlled by changing the revolutions of the fan pump <b>24</b> and by adjusting the valves <b>23</b> and <b>22</b>, when more flow is necessary the an pump <b>24</b> increases the revolutions and valve <b>23</b> increases the opening, valve <b>22</b> is adjusted to fine tune the required flow. In some installations the fan pump <b>24</b> has a constant speed motor in order to increase or decrease the flow out of the pump; in this case it is necessary to adjust valves <b>23</b> and <b>22</b>.

The wet sheet <b>10</b> is actually formed on the Fourdrinier table that consists essentially of endless forming mesh belt <b>11</b> which is supported in zones <b>4</b>, <b>5</b> and <b>6</b> by forming, and drainage devices which make up the wet end of the paper machine.

Close to the headbox <b>1</b>, the forming mesh is supported by the breast roll <b>3</b>, which is followed by forming, and drainage devices in zones <b>4</b>, <b>5</b>. The endless forming mesh moves over several suction boxes in zone <b>6</b> before it returns over a suction couch roll <b>7</b> and drive roil <b>9</b>.

Water is quantitatively the most important raw material of papermaking. Before the stock is discharged on the forming mesh <b>11</b> of the forming table, it is very dilute; its fiber content is probably as low as 0.1%. From this point on, water removal becomes one of the most decisive functions of the machine. The stock out of the headbox <b>1</b> contains other solids in addition to fibers, due to which it has approximately 0.5 percent consistency; and the fiber mat <b>10</b> out of the couch <b>7</b> has between 23 and 25 percent consistency.

However, that in order to reduce viscosity of the water and drain the water properly, it is necessary to heat the fiber slurry in the range of 135 to 140 degree Fahrenheit. During this process, it is normal to have heat losses in the range of 5 to 10 degree Fahrenheit.

Referring now to <figref idrefs="DRAWINGS">FIG. 9</figref>, fiber flow <b>1</b>A having consistency between 0.1% and 1% is discharged out of the headbox <b>1</b> through the headbox slice lip <b>2</b> onto a moving forming mesh <b>11</b>. The discharged velocity ratio (flow velocity divided by mesh velocity) between the fiber flow <b>1</b>A and the forming mesh <b>11</b> is normally in the range of 0.6 to 1.3. However, these machines can operate at speeds greater than 3,000 feet per minute.

The forming table of the paper making machine, which is depicted in <figref idrefs="DRAWINGS">FIG. 10</figref> in detail, is composed of three main sections, as follows:

A. The gravity and dynamic drainage zone <b>4</b>, where the sheet formation occurs. At the beginning of the formation zone <b>4</b> the fiber consistency is in the range of 0.1 and 1.0%, and at this point the fibers have high degree of freedom and here is where formation can be improved by enhancing the three hydrodynamic processes needed to form a paper sheet. At exit of gravity and dynamic drainage zone <b>4</b> the consistency is in the range of 1.5 to 2.0%, and after this zone, the formation can be improved just minimum.

B. The low and mid vacuum zone <b>5</b>—In this zone with the use of low vacuum boxes, small amount of vacuum is applied, vacuum is in the range of 2 to 60 inches of water, and consistency at exit of zone <b>5</b> is in the range of 6 to 8%.

The water drained by zones <b>4</b> and <b>5</b> is collected in receptacles <b>25</b> under the forming and drainage devices, and the water is directed to a storage tank <b>18</b> by channels <b>26</b> for reuse in stock dilution in the wet end close loop system, as shown in <figref idrefs="DRAWINGS">FIG. 8</figref>, for example.

C. The high vacuum drainage zone <b>6</b>, here is where sheet consolidation occurs, water is removed by using high vacuum boxes; vacuum applied is in the range of 2 to 16 inches of mercury. At the end of the wire section the couch <b>7</b> removes water with higher vacuum (20 to 22 inches of mercury) assisted by a press roll <b>8</b>. The water <b>12</b> drained in zone <b>6</b> is collected in a seal tank <b>13</b>, the pump <b>14</b> sends part of the water for level control <b>15</b> in tank <b>18</b>, the excess water <b>16</b> is sent to stock preparation system in conjunction with the overflow water <b>19</b> from water storage tank <b>18</b>.

After the fiber mat is consolidated in the high vacuum drainage zone <b>6</b> and press by the suction couch <b>7</b> and the lump breaker <b>8</b>, the sheet <b>10</b> leaves the forming table at consistencies between 23 and 27%.

As it was mentioned before, the short loop system at the wet end of the paper machine is the only system that can decrease or increase the consistency at the discharge of the headbox <b>1</b>.

As an example mass balances are presented, one in <figref idrefs="DRAWINGS">FIG. 10</figref> that shows the mass balance at 0.8% consistency out of headbox and another in <figref idrefs="DRAWINGS">FIG. 11</figref> that shows the mass balance at 0.5% consistency out of headbox.

It is important to note that in both mass balances the following operating parameters are exactly the same:

<tables id="TABLE-US-00001" num="00001"><table frame="none" colsep="0" rowsep="0"><tgroup align="left" colsep="0" rowsep="0" cols="3"><colspec colname="offset" colwidth="14pt" align="left" /><colspec colname="1" colwidth="98pt" align="left" /><colspec colname="2" colwidth="105pt" align="char" /><thead><row><entry /><entry namest="offset" nameend="2" align="center" rowsep="1" /></row></thead><tbody valign="top"><row><entry /><entry>Headbox recirculation</entry><entry>5.0%</entry></row><row><entry /><entry>1st Cleaning system rejects by</entry><entry>2.0%</entry></row><row><entry /><entry>weight</entry></row><row><entry /><entry>1st Rejects thickening factor</entry><entry>1.4</entry></row><row><entry /><entry>2nd Cleaning system rejects by</entry><entry>10.0%</entry></row><row><entry /><entry>weight</entry></row><row><entry /><entry>2nd Rejects thickening factor</entry><entry>4</entry></row></tbody></tgroup><tgroup align="left" colsep="0" rowsep="0" cols="4"><colspec colname="offset" colwidth="14pt" align="left" /><colspec colname="1" colwidth="98pt" align="left" /><colspec colname="2" colwidth="28pt" align="right" /><colspec colname="3" colwidth="77pt" align="left" /><tbody valign="top"><row><entry /><entry>Machine Speed</entry><entry>2000</entry><entry>Feet per minute</entry></row><row><entry /><entry>Headbox width</entry><entry>200</entry><entry>Inch</entry></row><row><entry /><entry>Paper basis weight</entry><entry>26</entry><entry>Lbs/1000 Square feet</entry></row><row><entry /><entry>Paper production at 10 out</entry><entry>624.0</entry><entry>Short Tons per day</entry></row><row><entry /><entry>of the forming table</entry></row><row><entry /><entry namest="offset" nameend="3" align="center" rowsep="1" /></row></tbody></tgroup></table></tables>

As a result the production <b>10</b> out of the forming table is exactly the same in both balances as follows:

<tables id="TABLE-US-00002" num="00002"><table frame="none" colsep="0" rowsep="0"><tgroup align="left" colsep="0" rowsep="0" cols="3"><colspec colname="offset" colwidth="35pt" align="left" /><colspec colname="1" colwidth="91pt" align="left" /><colspec colname="2" colwidth="91pt" align="char" /><thead><row><entry /><entry namest="offset" nameend="2" align="center" rowsep="1" /></row></thead><tbody valign="top"><row><entry /><entry>Sheet solids short tons per day</entry><entry>624</entry></row><row><entry /><entry>Sheet Consistency %</entry><entry>23</entry></row><row><entry /><entry>Gallons per Minute</entry><entry>453</entry></row><row><entry /><entry namest="offset" nameend="2" align="center" rowsep="1" /></row></tbody></tgroup></table></tables>

The sheet formation is better when consistency out of the headbox is at 0.5% than 0.8%, and performance of the equipment is completely different in both cases. The main difference in these two balances is inside the short loop system as follows:

<tables id="TABLE-US-00003" num="00003"><table frame="none" colsep="0" rowsep="0" pgwide="1"><tgroup align="left" colsep="0" rowsep="0" cols="4"><colspec colname="offset" colwidth="91pt" align="left" /><colspec colname="1" colwidth="105pt" align="center" /><colspec colname="2" colwidth="105pt" align="center" /><colspec colname="3" colwidth="105pt" align="center" /><tbody valign="top"><row><entry /><entry namest="offset" nameend="3" align="center" rowsep="1" /></row><row><entry /><entry /><entry /><entry>Increase in mass flow handling due</entry></row><row><entry /><entry>Mass balance at 0.8% consistency</entry><entry>Mass balance at 0.5% consistency</entry><entry>to reduction in consistency from</entry></row><row><entry /><entry>out of headbox</entry><entry>out of headbox</entry><entry>0.8 to 0.5% at headbox</entry></row></tbody></tgroup><tgroup align="left" colsep="0" rowsep="0" cols="9"><colspec colname="offset" colwidth="91pt" align="left" /><colspec colname="1" colwidth="42pt" align="center" /><colspec colname="2" colwidth="28pt" align="center" /><colspec colname="3" colwidth="35pt" align="center" /><colspec colname="4" colwidth="42pt" align="center" /><colspec colname="5" colwidth="28pt" align="center" /><colspec colname="6" colwidth="35pt" align="center" /><colspec colname="7" colwidth="56pt" align="center" /><colspec colname="8" colwidth="49pt" align="center" /><tbody valign="top"><row><entry /><entry>STPD</entry><entry>%</entry><entry>GPM</entry><entry>STPD</entry><entry>%</entry><entry>GPM</entry><entry>STPD</entry><entry>GPM</entry></row><row><entry /><entry namest="offset" nameend="8" align="center" rowsep="1" /></row></tbody></tgroup><tgroup align="left" colsep="0" rowsep="0" cols="9"><colspec colname="1" colwidth="91pt" align="left" /><colspec colname="2" colwidth="42pt" align="char" char="." /><colspec colname="3" colwidth="28pt" align="center" /><colspec colname="4" colwidth="35pt" align="char" char="." /><colspec colname="5" colwidth="42pt" align="char" char="." /><colspec colname="6" colwidth="28pt" align="center" /><colspec colname="7" colwidth="35pt" align="center" /><colspec colname="8" colwidth="56pt" align="center" /><colspec colname="9" colwidth="49pt" align="center" /><tbody valign="top"><row><entry>Headbox 1 discharge</entry><entry>764.2</entry><entry>0.80</entry><entry>15,953</entry><entry>942.9</entry><entry>0.50</entry><entry>31,492</entry><entry>178.6</entry><entry>15,539</entry></row><row><entry>Drained water at zone 4</entry><entry>89.3</entry><entry>0.16</entry><entry>9,323</entry><entry>268.0</entry><entry>0.18</entry><entry>24,862</entry><entry>178.6</entry><entry>15,539</entry></row><row><entry>Dilution water to fan pump 24</entry><entry>117.9</entry><entry>0.16</entry><entry>12,578</entry><entry>294.7</entry><entry>0.18</entry><entry>28,111</entry><entry>176.8</entry><entry>15,533</entry></row><row><entry>Inlet flow to screen 27</entry><entry>820.9</entry><entry>0.80</entry><entry>17,038</entry><entry>1012.8</entry><entry>0.50</entry><entry>33,633</entry><entry>191.9</entry><entry>16,595</entry></row><row><entry>inlet flow to headbox 1</entry><entry>804.4</entry><entry>0.80</entry><entry>16,793</entry><entry>992.5</entry><entry>0.50</entry><entry>33,149</entry><entry>188.1</entry><entry>16,357</entry></row><row><entry namest="1" nameend="9" align="center" rowsep="1" /></row><row><entry namest="1" nameend="9" align="left" id="FOO-00001">STPD Short tons per day</entry></row><row><entry namest="1" nameend="9" align="left" id="FOO-00002">GPM Gallons per minute</entry></row><row><entry namest="1" nameend="9" align="left" id="FOO-00003">% Consistency</entry></row></tbody></tgroup></table></tables>

By decreasing consistency from 0.8% to 0.5%, the hydraulic flow has been increased by 15,913 GPM as an average, and solids are increased by 183 STPD as an average. In order to move the additional flow it is necessary to increase the power of the motors of the fan pump <b>24</b> and the screens <b>27</b> and <b>32</b>, and in many instances it is necessary to change the equipment.

Due to excessive flow when working at low consistency of 0.5%, more chemicals are needed; drainage at zones <b>4</b> and <b>5</b> becomes more difficult. Performance of the headbox is deteriorated if there is too much turbulence due to an excessive flow; cross currents are created that lead to uneven stock delivery to the sheet forming zone. A headbox which is not functioning properly can cause many defects in the finished sheet. The worst of these is poor formation that results when fibers are not dispersed evenly or uniformly.

By working at 0.8% consistency instead of 0.5%, there is a considerable reduction in the flow to the head box; approximately by 15,913 GPM. As a result there is less steam necessary to keep the slurry at its operating temperature, which means a reduction of 807,946 Btu/min for a 5 degree drop in temperature. It will be noted that with respect to companies that use fuel oil for heating purposes, this could mean a reduction of emission of 4640 tons of carbon dioxide per year to the atmosphere, and with respect to companies that use gas for heating purposes, the reduction of carbon dioxide to the atmosphere is approximately 416 tons per year.

In addition to the above, the excess water <b>19</b> sent back to water treatment has less solids (1.8 tons per day less) as can be appreciated from <figref idrefs="DRAWINGS">FIGS. 10 and 11</figref>.

One aspect of the present invention can be seen in <figref idrefs="DRAWINGS">FIGS. 12-19</figref>, for example. In <figref idrefs="DRAWINGS">FIG. 13</figref>, blade <b>36</b> has a support blade <b>37</b>A that has two important functions, one is to maintain the forming fabric separated from the blade <b>36</b> in combination with the support blade <b>37</b>, the other most important function is to allow the previously drained water <b>1</b>D to pass underneath the support blade <b>37</b>A. The exit side of the blade <b>36</b> has a sloped surface <b>36</b>A that diverts from the forming fabric <b>11</b> in an angle between 0.1 and 10.0 degrees, the drained water from the fiber slurry <b>1</b>A, will pass under the support blade <b>37</b>, the drained water <b>57</b> will merge with the recirculation water <b>62</b>, to form a continuous increased flow <b>58</b>, large part of this flow will be reintroduced to the fiber slurry <b>1</b>A that will become fiber slurry flow <b>1</b>B which will have lower consistency than flow <b>1</b>A. Reduction in consistency is controlled by opening or closing the gate <b>38</b> that is held in place by the bottom plate <b>63</b> and the support <b>64</b>. The gate <b>38</b> allows to increase or decrease discharged flow <b>42</b>. By closing or opening the gate <b>38</b>, flow <b>62</b> changes to desired level, as consequence the consistency at <b>1</b>B may be controlled to produce a uniform mat of fiber on cross machine direction and on machine direction as well. The support blade <b>37</b> and the trail blade <b>39</b> keep the forming fabric <b>11</b> separated from the central plate <b>35</b>. The gap between the forming fabric <b>11</b> and the central plate is always filled with water drained from the fiber slurry <b>1</b>A, and due to the continuous flow of water, the friction between the central plate <b>35</b> and the forming fabric <b>11</b> is minimal. At the end of the central plate <b>35</b> is located the drainage zone <b>56</b>, at this point the surface of the central plate <b>35</b> slopes away from the forming fabric <b>11</b>, and the surface <b>71</b> with the slope may have anything from 0.1 up to 10 degrees of separation, although it is preferred not to exceed 7 degrees. This kind of geometry recirculates the water <b>34</b> from slurry <b>1</b>B as it is shown in <figref idrefs="DRAWINGS">FIG. 13</figref> by the stream lines <b>59</b>, <b>60</b> and <b>61</b>, in order to be reintroduced by stream <b>58</b>. The central plate <b>35</b> and the bottom plate <b>63</b> form a channel <b>73</b> wherein both pieces are separated by spacers <b>66</b> that allow the drained water <b>34</b> scraped by trail blade <b>39</b> to move forward to channel <b>74</b>, at this point the recirculation flow <b>62</b> merges with drained flow <b>57</b> to form stream flow <b>58</b> that will be reintroduced to fiber slurry <b>1</b>A in order to lower the consistency at <b>1</b>B at any desired level. It is due to the formation of channel <b>73</b> that the merger of two flows at different velocities occurs and high shear effect is produced in section <b>54</b>. It is important to note, however, that gate <b>38</b> controls the amount of purge flow <b>42</b>. Due to the inherent flow and high shear effect created using the design of the system according to the present invention, it is not necessary to increase the power of the motors of the fan pump <b>24</b> or the screens <b>27</b> and <b>32</b>. The instant design, for example, the separation of central plate <b>35</b> and the bottom plate <b>63</b> to form channel <b>73</b> that allows recirculating the instant drained water, results in lower energy consumption when compared to a traditional system.

After drainage zone <b>56</b>, the consistency of fiber slurry <b>1</b>C is same as <b>1</b>A or higher, depending on the amount of water <b>42</b> drained by gate <b>38</b>. The central plate <b>35</b> holds the support blade <b>37</b>, the central plate <b>35</b> is in a fixed position in order to maintain the specified distances from the central plate to the forming fabric <b>11</b>, to the inlet blade <b>36</b>, to the trail blade <b>39</b> and to the bottom plate <b>63</b>, those distances are designed according to the process needs for specific paper machine, the central plate <b>35</b> is fixed by one, two or as many T bars <b>68</b> as needed according to the length of the self dilution, shear, microactivity and drainage section. T bars are fixed in position by bolts <b>65</b> and spacers <b>66</b>. The surface <b>71</b> of the central plate <b>35</b> at drainage section is diverging from the forming fabric <b>11</b>, and the slope may have anything from 0.1 up to 10 degrees of separation, and pre erred not to exceed 7 degrees.

The length of central plate <b>35</b> in <figref idrefs="DRAWINGS">FIGS. 13</figref>, <b>14</b>, <b>15</b>, <b>16</b>, <b>17</b>, <b>18</b>, <b>19</b> and central plate <b>53</b> in <figref idrefs="DRAWINGS">FIG. 20</figref> is designed according to the process needs for specific paper machine. Length of central plate will also depend on the machine speed, basis weight and the amount of the consistency reduction needed.

<figref idrefs="DRAWINGS">FIG. 21</figref> shows location of the new invention <b>75</b> at the gravity and dynamic drainage in the sheet formation zone <b>4</b>; <figref idrefs="DRAWINGS">FIG. 22</figref> shows detailed location of the new invention <b>75</b> at the gravity and dynamic drainage in the sheet formation zone <b>4</b>.

<figref idrefs="DRAWINGS">FIG. 23</figref> shows the location of the new invention <b>76</b> at the gravity and dynamic drainage in the sheet formation zone <b>4</b>; <figref idrefs="DRAWINGS">FIG. 24</figref> shows detail location of the new invention <b>76</b> at the gravity and dynamic drainage in the sheet formation zone <b>4</b>.

The new invention installed at gravity and dynamic drainage in the sheet formation zone <b>4</b> erases the necessity of lowering the fiber slurry consistency at the head box, and as a result will give same benefits as working with traditional system (lower the consistency in whole system).

As an example of benefits obtained with new invention in sheet formation physical properties and productivity when the paper machine is working with low consistency are in mass balance in <figref idrefs="DRAWINGS">FIG. 12</figref>. Said benefits may be obtained by working with the new invention installed as per <figref idrefs="DRAWINGS">FIGS. 21</figref>, <b>22</b>, <b>23</b> and <b>24</b>, instead of traditional system.

A mass balance with the new invention is presented in <figref idrefs="DRAWINGS">FIG. 12</figref>; benefits of working with the new invention are as follows: <ul><li id="ul0001-0001" num="0121">I. Lower energy consumption when working with the new invention than working with traditional system.</li><li id="ul0001-0002" num="0122">II. There is no need to change the actual equipment for a large one such as machinery and or piping.</li><li id="ul0001-0003" num="0123">III. Lower emissions into the atmosphere because of less steam or fuel necessary to heat the fiber slurry.</li><li id="ul0001-0004" num="0124">IV. More environmental friendly because less solids are sent to the water treatment unit.</li><li id="ul0001-0005" num="0125">V. Fewer solids in the water system.</li><li id="ul0001-0006" num="0126">VI. Less use of chemicals.</li><li id="ul0001-0007" num="0127">VII. Better paper quality when working with the new invention than working with traditional system because the new invention in addition to reducing the consistency also produces at the same time the three hydrodynamic processes needed to make paper.</li><li id="ul0001-0008" num="0128">VIII. The design operating velocities inside of machinery such as headbox <b>1</b>, screens <b>27</b> and <b>32</b> are always inside the design limits when operation is made with the new invention, because the design flows are not exceeded.</li><li id="ul0001-0009" num="0129">IX. Fiber lost is less with the new invention.</li><li id="ul0001-0010" num="0130">X. Recirculates the same drainage water right after leaving the forming fabric not even leaving the forming table.</li><li id="ul0001-0011" num="0131">XI. There is no fiber contamination from other sources; this benefit makes the process more stable.</li><li id="ul0001-0012" num="0132">XII. There is not temperature change in the forming section <b>4</b>.</li><li id="ul0001-0013" num="0133">XIII. There is no air entrapped in the system.</li><li id="ul0001-0014" num="0134">XIV. There is no change in retention.</li><li id="ul0001-0015" num="0135">XV. A change paper grade is easy because the volume inside the new invention is a small amount.</li><li id="ul0001-0016" num="0136">XVI. It is a continuous recirculation plug flow.</li><li id="ul0001-0017" num="0137">XVII. Radial design of surface <b>69</b> evens the flow <b>58</b> reducing the fiber mat variability on cross machine direction as it is shown in <figref idrefs="DRAWINGS">FIG. 30</figref>.</li><li id="ul0001-0018" num="0138">XVIII. There is no filtration process in the early part of the blade.</li><li id="ul0001-0019" num="0139">XIX. The power to drive the wire is reduced because friction between the wire and the blade is minimum, and total flow on top of the forming table is reduced.</li><li id="ul0001-0020" num="0140">XX. There is no dirt accumulation on the blade because there is continuous flow of water.</li><li id="ul0001-0021" num="0141">XXI. The fibers on the wire are redistributed and activated with the same water.</li><li id="ul0001-0022" num="0142">XXII. Fiber retention is increased.</li><li id="ul0001-0023" num="0143">XXIII. Formation is improved.</li><li id="ul0001-0024" num="0144">XXIV. Squareness of the sheet is controlled as is necessary.</li><li id="ul0001-0025" num="0145">XXV. Drainage is also controlled.</li><li id="ul0001-0026" num="0146">XXVI. Fibers are evenly distributed across the thickness of the sheet.</li><li id="ul0001-0027" num="0147">XXVII. Physical properties of the paper are improved or controlled as they are necessary.</li></ul>

<figref idrefs="DRAWINGS">FIG. 25</figref> presents the new invention with the self dilution, multiple shear, microactivity and drainage section, having a constant gap D<b>1</b> between the forming fabric <b>11</b> and the central plate <b>48</b>.

<figref idrefs="DRAWINGS">FIG. 26</figref> presents the new invention with the self dilution, multiple shear, microactivity and drainage section, having an increasing gap D<b>2</b>, D<b>3</b> and D<b>4</b> between the forming fabric <b>11</b> and the central plate <b>49</b>.

<figref idrefs="DRAWINGS">FIG. 27</figref> presents the new invention with the self dilution, multiple shear, microactivity and drainage section, having an offset plane surface <b>72</b> between the forming fabric <b>11</b> and the central plate <b>50</b>.

<figref idrefs="DRAWINGS">FIG. 28</figref> presents the new invention with the self dilution, multiple shear, microactivity and drainage section, with detail description the offset plane surfaces between the forming fabric <b>11</b> and the central plate <b>50</b>, surface <b>72</b>A is offset of surface <b>72</b>B by step <b>72</b>, and the hydrodynamic action observed here was described in FIBER MAT FORMING APPARATUS AND METHOD OF PRESERVING THE HYDRODYNAMIC PROCESSES NEEDED TO FORM A PAPER SHEET by Cabrera, Patent Application Publication No.: US 2009/0301677 A1.

<figref idrefs="DRAWINGS">FIG. 29</figref> presents the new invention with the self dilution, multiple shear, microactivity and drainage section, having a pivot point at drainage area of the central plate <b>52</b> in order to control the activity and amount of water to be drained. The pivot point allows section <b>52</b>A to be adjusted as the process needs.

<figref idrefs="DRAWINGS">FIG. 30</figref> presents the new invention with the self dilution, multiple shear, microactivity and drainage section with detail explanation of different sections as follows:

A. Self Dilution and Shear Section <b>54</b>:

This section begins at leading edge of support <b>37</b> and ends at end of radial section <b>69</b>. The length of this section depends on the machine speed, and the amount of water <b>58</b> to be introduced to the fiber slurry <b>1</b>A. Stream flow <b>58</b> is composed by streams flows <b>57</b> and <b>62</b>, and stream flow <b>62</b> follows the path of channel <b>74</b> which allows to have a continuous and uniform flow that later will merge with flow <b>57</b> and be delivered into the forming fabric <b>11</b> to become flow <b>1</b>B. The amount of stream flow <b>62</b> is controlled by the amount of water <b>42</b> purged through gate <b>38</b>.

High shear effect is developed in this section by controlling differential velocities between flows <b>1</b>A and flow <b>58</b>, after these flows merge, high dilution in flow <b>1</b>A takes place and microactivity is initiated. The radial design of surface <b>69</b> evens the flow <b>58</b>, reducing the fiber mat variability in cross machine direction.

Length of self dilution and shear section depends on machine speed, basis weight and consistency decrease.

B. Microactivity at Low Consistency <b>55</b>:

Surface <b>70</b> of central plate <b>35</b> may have different configuration as was described early in this document, and also in FIBER MAT FORMING APPARATUS AND METHOD OF PRESERVING THE HYDRODYNAMIC PROCESSES NEEDED TO FORM A PAPER SHEET by Cabrera, Patent Application Publication No.: US 2009/0301677 A1. There is a gap between the surface <b>70</b> of the central plate <b>35</b> and the wire <b>11</b>, this feature allows having water in between them provoking microactivity and shear effect, at this section is where the lowest consistency is obtained.

Length of microactivity at low consistency section will depend on machine speed, basis weight and type of fiber.

C. Drainage <b>56</b>:

Stream flow <b>59</b> in <figref idrefs="DRAWINGS">FIGS. 30 and 31</figref> occur in last section of central plate <b>35</b>. The surface <b>71</b> of the central plate <b>35</b> at drainage section is diverging from the forming fabric <b>11</b>. The slope may have anything from 0.1 up to 10 degrees of separation, preferably not to exceed 7 degrees. Length of drainage section will depend on the amount of flow to be drained. The flow <b>59</b> continues to flow <b>60</b> through channel <b>77</b> that is located in between last part of central plate and trail blade <b>39</b>. Channel <b>77</b> is designed in order to avoid fiber stapling and to have minimum friction losses, stream flow continues through channel <b>73</b>.

In case that wire <b>11</b> deflects and contacts the central plate, second support blade <b>37</b>B is added, as it is shown in <figref idrefs="DRAWINGS">FIG. 31</figref>. At end of surface <b>70</b> of central plate <b>35</b> a radial surface <b>71</b>A follows in continuation in order to maintain stream flow <b>59</b> in continuous contact with central plate <b>35</b> (avoid flow separation).

<figref idrefs="DRAWINGS">FIG. 32</figref> presents detail explanation of the hydraulics at the self dilution and shear section of the new invention. Support blade <b>37</b> prevents the wire from deflecting and coming in contact with central plate <b>53</b>, the stream flow drained from fiber slurry <b>1</b>B passes underneath the support blade and later is reintroduced to the fiber slurry were shear effect takes place.

<figref idrefs="DRAWINGS">FIG. 33</figref> presents detail explanation of the geometry that holds the central plate <b>35</b>. Bolts <b>65</b> and spacers <b>66</b>, for example, may be used between bottom plate <b>63</b> and central plate <b>35</b> to help form channel <b>73</b>.

In an alternative embodiment as shown in <figref idrefs="DRAWINGS">FIG. 34</figref>, for example, T bars <b>68</b> and spacers <b>66</b> may be used between bottom plate <b>63</b> and central plate <b>35</b> to hold the central plate <b>35</b> and form channel <b>73</b>.

<figref idrefs="DRAWINGS">FIG. 35</figref> presents detail explanation of the T bar <b>68</b> geometry. Distance <b>68</b>B between Tap holes <b>68</b>A varies between 4 and 10 inches, and it is specifically designed for each paper machine. Distance L<b>1</b> and L<b>2</b> are equal, this section is the portion that connects directly with spacers <b>66</b> or the main structure of the box. Distance L<b>3</b> and L<b>4</b> are different from each other, in this case L<b>3</b> is larger than L<b>4</b> but can be the other way around without losing the principle. The head of the T bar <b>68</b>C is the part that connects directly with the central plate <b>35</b> in this case or may be with any blade, due to difference in distance L<b>3</b> and L<b>4</b> the central plate <b>35</b> and or any blade will slide in only in one direction.

<figref idrefs="DRAWINGS">FIGS. 36</figref>, <b>37</b>, <b>38</b> and <b>39</b> presents detail explanation of the hydraulic performance of the new invention. <figref idrefs="DRAWINGS">FIG. 36</figref>, the effect created by blade <b>36</b> and support blade <b>37</b>A was explained in FIBER MAT FORMING APPARATUS AND METHOD OF PRESERVING THE HYDRODYNAMIC PROCESSES NEEDED TO FORM A PAPER SHEET by Cabrera, Patent Application Publication No.: US 2009/0301677 A1, the entire contents of which is incorporated herein by reference. The stream flow <b>57</b> merges with stream flow <b>62</b> flowing underneath support blade <b>37</b> in order to be reintroduced <b>58</b> to fiber slurry <b>1</b>A, in section <b>54</b> high shear effect is produced, caused by the merger of two flows at different velocities, it is important to note gate <b>38</b> controls the amount of purge flow <b>42</b>.

<figref idrefs="DRAWINGS">FIGS. 38 and 39</figref> presents detail explanation of drainage process, where surface <b>71</b> slopes away from the forming fabric <b>11</b>, the slope may have anything from 0.1 up to 10 degrees of separation, but preferably not to exceed 7 degrees. This kind of geometry produces vacuum due to the loss of potential energy, and drained water follows path of stream lines <b>60</b> and <b>61</b>. In case distance from support blade <b>37</b> and trail blade <b>39</b> is large and the forming fabric <b>11</b> touches the central plate <b>35</b>, additional support blade <b>37</b>B may be installed, radial surface <b>71</b>A is installed in order to avoid flow <b>59</b> separation from central plate <b>35</b>, flow continues through channels <b>77</b> and later on channel <b>73</b>.

Chemical Addition

In another embodiment, paper making chemicals as known to those of ordinary skill in the art are added to fiber suspension in order to enhance paper strength and machine productivity. All paper chemicals are added before or after the forming table.

The efficiency of the chemicals is greatly reduced when added before the forming table because of the large dilution and high volume water recirculation at the forming section, in addition to the above, the response time to any change in chemical dosage is not immediate.

When chemicals are added after the forming table, normally is done at the size press in this case the speed of the paper machine is reduced between 13 to 25% or it is necessary to add more dryers in order to evaporate the additional water in the paper web, in both situations there is more use of energy.

Each grade of paper requires a specific combination of furnish ingredients which are selected according to the specifications of the paper being produced.

As it is shown in <figref idrefs="DRAWINGS">FIG. 13A</figref>, the chemicals <b>100</b> are injected through pipe <b>99</b> said chemicals merge and mix with previously drained flow <b>59</b>. Chemicals <b>100</b> and drained water <b>59</b> merge at zone <b>60</b> creating a turbulence zone <b>34</b>B where there is a complete dilution of chemicals; mixed flow <b>60</b> and <b>61</b> continues through channel <b>73</b> said flow is agitated by spacers <b>66</b> that are separated across machine direction which main purpose is to form channel <b>73</b> and support the T bars <b>68</b>. Pipes <b>99</b> feeding the chemicals are spaced cross machine direction separated from 0.5 to 8 inches depending on the paper machine needs 4 to 6 inches is the preferred separation.

The unit may work with or without chemical addition; in case of chemical addition it is preferable to close the gate valve <b>38</b> in order to eliminate any chemical lost.

The water and chemicals mixed flow <b>61</b> and later <b>62</b> merges with new drain flow <b>57</b> and it is reintroduced <b>58</b> to the fiber suspension <b>1</b>A, both flows become as flow <b>1</b>B, fibers are completely saturated with chemicals at microactivity zone <b>55</b>, not retained chemicals are drained as part of flow <b>59</b> in order to be reused again optimizing chemical use.

In relation to a size press it is worth to note that the chemicals added at this stage increases the dry strength of the paper with minimum refining and low fiber quality, the chemicals added at the size press are in solution at approximately 3 to 25% solids, the paper absorbs some of the sizing solution and the balance is removed at the press. The size press solution absorbed by the paper has to be eliminated with additional dryers after the size press.

<figref idrefs="DRAWINGS">FIG. 13A</figref> depicts the new forming invention showing the chemical injection.

<figref idrefs="DRAWINGS">FIG. 13B</figref> depicts the new forming invention, details the chemical injection.

The benefits of making the chemical injection at the forming table with the new invention are as follows:

1. The efficiency of the chemicals is higher as long as chemicals are not diluted because the volume that the new invention uses is minimum compared with the total volume stored at the silo.

2. The efficiency of chemicals is better because chemicals and fibers are well mixed at the microactivity zone.

3. The chemical are not subject to high shear effect like happen at the fan pump or machine screen, shear action reduces efficiency of chemicals.

4. There is considerable reduction in energy consumption when chemical added at the new invention replaces chemicals at the size press, because it is not necessary to eliminate the excess liquid absorbed by the paper.

5. There is not machine speed reduction due to rewetting of the paper sheet at size press in the dryers.

6. It is possible to control the strength of the paper in cross machine direction.

7. The response to any change in dosage is immediate because the new invention works with minimum volume of water compared to the volume of the silo.

While the invention has been described in connection with what is considered to be the most practical and preferred embodiment, it should be understood that this invention is not limited to the disclosed embodiments, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.